b2. H. pylori-positive cases at diagnosis, who failed antibiotic therapy, including patients with: clinical (endoscopic) and histological evidence of disease progression at any time post H. pylori eradication; stable disease with persistent lymphoma at 1 year post H. pylori eradication; relapse (without H. pylori re-infection), after a remission; patients who failed either first line antibiotics or further local treatment (surgery or radiotherapy)